NASA today announced that it will delay this month's planned
shipment of its Chandra X-ray Observatory from prime contractor TRW
Space and Electronics Group, Redondo Beach, CA, to NASA's Kennedy
Space Center , FL. The postponement will allow TRW to evaluate and
correct a potential problem with several printed circuit boards in
the observatory's command and data management system.

TRW notified NASA of the potential problem last week after another
spacecraft being built by the company experienced a failure during
testing that was attributed to similar printed circuit boards. The
failed boards and those in Chandra were all made by BF Goodrich
Aerospace, Davis Systems Div., Albuquerque, NM, in the same time
frame in 1996. The problem has been traced to poor conductivity
between different layers of the boards.

The boards are used in Chandra's main command and telemetry unit and
four remote units. These units provide command and data
communications links between the observatory's computer and
subsystems.

NASA has directed TRW to remove and replace the boards in the main
unit, and to conduct further tests and evaluation to determine if it
is also necessary to replace the boards in the remote units. The
repair, if limited to boards in the main command and telemetry unit,
is expected to delay shipment to Kennedy by approximately one week.
This will result in approximately a five-week slip in the
observatory's launch readiness date, which will allow for integration
and testing of the units at Kennedy. If boards in the remote units
must also be replaced, a more extensive slip is anticipated.